With TPB it is possible to bind a program to the ThinkPad, Mail,
Home and Search buttons.  TPB can also run a callback program on
each state change with the changed state and the new state as
options, so it is possible to trigger several actions on different
events.

TPB has an on-screen display (OSD) to show volume, mute, brightness
and some other information.

Please note that TPB doesn't always work with MP enabled kernels because
of issues with /dev/nvram
